This application relates to crystalline aluminosilicates, commonly called zeolites, and used as builders in formulated detergents. In particular, our invention comprises a zeolite-alkali metal silicate composite that disintegrates in aqueous media, allowing the zeolite to disperse rapidly in said aqueous media.
Zeolites (crystalline or partially crystalline alkali metal aluminosilicates) have been used to replace or partially replace phosphates in built laundry detergents as described in U.S. Pat. Nos. 3,985,669; 4,000,094; 4,019,999 and 4,096,081. The prior art section of Patent 4,096,081 describes many of the problems associated with the use of zeolites as builders in detergents. Some of these problems are: (1) zeolite built detergents cannot be formulated with sufficient alkali metal silicate to realize the desirable detersive properties of the silicate; (2) zeolites of the proper particle size for detergent builders are free-flowing, but present a severe dusting problem when being handled; (3) high density and small particle size materials such as zeolites and silicates tend to segregate from dry blended mixtures upon handling and storage. The solution to these problems offered by this prior art patent is to prepare granules containing the aluminosilicate builder separately from the portion of the detergent containing the soluble silicate. The teachings of this patent further indicate that even in an agglomerate there is an undesirable "polymerization" of the zeolite when the silicate is present in the agglomerate.
The considerable body of prior art directed to the use of zeolites as detergent builders all indicates that the ion exchange capacity of the zeolite for calcium must be high and that the dispersion of the zeolite throughout the wash water must not be impeded in any way. It is therefore imperative that any agglomerate involving zeolite builder must disintegrate in such a manner that the zeolite can disperse in the wash water as quickly as possible upon exposure to the aqueous medium.